J Appl Oral Sci. 14 ABSTRACT www.scielo.br/jaos http://dx.doi.org/10.1590/1678-775720140124 TiF 4 and NaF varnishes as anti-erosive agents on enamel and dentin erosion progression in vitro Livia Picchi COMAR, Cristiane de Almeida Baldini CARDOSO, Senda CHARONE, Larissa Tercilia GRIZZO, Marília Afonso Rabelo BUZALAF, Ana Carolina MAGALHÃES Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. Corresponding address: Ana Carolina Magalhães - Departmento de Ciências Biológicas - Faculdade de Odontologia de Bauru - Universidade de São Paulo - Al. Octávio Pinheiro Brisolla, 9-75 - 17012-901 - Bauru - SP - Brazil - Phone/Fax: +55 (14) 3235-8497 - e-mail: acm@fob.usp.br Submitted: March 19, 2014 - Modifcation: July 14, 2014 - Accepted: July 29, 2014 O bjective: This study assessed the effect of fuoride varnishes on the progression of tooth erosion in vitro. Material and Methods: Forty-eight enamel and 60 root dentin samples were previously demineralized (0.1% citric acid, pH 2.5, 30 min), leading to a baseline and erosive wear of 12.9 and 11.4 µm, respectively. The samples were randomly treated (6 h) with a 4% TiF 4 varnish (2.45%F-, pH 1.0), a 5.42% NaF varnish (2.45%F-, pH 5.0), a placebo varnish and no varnish (control). The samples were then subjected to erosive pH cycles (4x90 s/day in 0.1% citric acid, intercalated with artifcial saliva) for 5 days. The increment of the erosive tooth wear was calculated. In the case of dentin, this fnal measurement was done with and without the demineralized organic matrix (DOM). Enamel and dentin data were analyzed using ANOVA/Tukey’s and Kruskal-Wallis/Dunn tests, respectively (p<0.05). Results: The TiF 4 (mean±s.d: 1.5±1.1 µm) and NaF (2.1±1.7 µm) varnishes signifcantly reduced enamel wear progression compared to the placebo varnish (3.9±1.1 µm) and control (4.5±0.9 µm). The same differences were found for dentin in the presence and absence of the DOM, respectively: TiF 4 (average: 0.97/1.87 µm), NaF (1.03/2.13 µm), placebo varnish (3.53/4.47 µm) and control (3.53/4.36 µm). Conclusion: The TiF 4 and NaF varnishes were equally effective in reducing the progression of tooth erosion in vitro. Keywords: Sodium fuoride. Titanium. Tooth erosion. INTRODUCTION Dental erosion is a clinical condition that is currently being studied since researchers have reported an increase in its prevalence 17 . Furthermore, dentists are becoming more aware about the etiology and early detection of this condition 23 . Acid exposure causes enamel surface demineralization, and long-term demineralization leads to erosive enamel wear as a consequence of progressive mineral loss 15 . Dentin erosion presents a different histology lesion, since the progression of demineralization is modulated by the presence of the demineralized organic matrix (DOM) 6,11 . The DOM may be affected by enzymatic and chemical degradation, which may enhance the progression of dentin wear over time 7,27 . The primary preventive measure for dental erosion is to reduce the frequency and duration of acid exposure 22 . As it is diffcult to control the behavior of the patient, such as the frequency of acid intake or special drinking habits, other strategies have been proposed to control dental erosion that are rather less dependent on the compliance of the patient. The most tested alternative is to increase the acid resistance of the teeth through the application of fluoride. Accordingly, highly concentrated fuoride applications such as oral rinses, gels and varnishes have been tested 5 . The application of NaF at high concentration is able to promote a CaF 2 -like layer precipitation on enamel 26 . The CaF 2 globules behave as a physical barrier, inhibiting the contact of the acid with enamel and/or acting as a fuoride reservoir. However, this layer presents low acid resistance 10 , thus, its effcacy in controlling dental erosion is restricted, at least under in vitro conditions 10 . 2015;23(1):14-8